Immunology Flashcards
What 4 things does the immune system need to do?
Detect threat
Respond against threat
Minimise collateral damage
Remember threat to respond effectively if reencountered
What is an interferon?
A molecule that interferes with viral replication
What is a natural killer cell?
Recognises virally infected cells and destroys them
What do cytotoxic T cells do?
Recognise and eliminate affected cells
Give 4 differences between innate and adaptive immunity
Innate is independent of previous exposure whereas adaptive is adapted to exposure
Innate uses preformed and rapidly synthesised components whereas adaptive depends on clonal selection.
Innate takes minutes/ hours whereas adaptive is slow and takes days
Innate relies on pattern recognition and has limited specificity whereas adaptive is highly specific to foreign antigens.
What is a PAMP and what is a DAMP?
Pathogen associated molecular patterns and damage associated molecular patterns
How are receptors encoded in innate immunity cells?
Receptors are directly encoded in genes, or the germ-line
How are adaptive immunity receptors encoded?
Random recombination of gene segments
Compared and contrast innate immunity receptors with adaptive immunity receptors?
With innate immunity many cells express the same receptor resulting in a rapid response whereas in adaptive immunity initially very few cells express a specific receptor, so they must be greatly expanded to generate an effective response
Innate has limited receptor diversity, meaning some pathogens are not effectively recognised, whereas adaptive immunity means there is a huge massive diversity of receptors and all structures may potentially be recognised. However there is a potential risk for autoimmunity due to the random nature of receptor generation.
What is a B cell receptor?
A membrane bound antibody which binds to intact antigens
What is a T cell receptor?
2 protein chains (alpha and beta) which bind to “processed” antigen fragments presented at cell surfaces
What is a cytokine?
Small secreted proteins which play a key role in cell to cell communication. They are the “messengers” of the immune system and they generally act locally.
Give 5 families of cytokines?
Interferons - anti viral Interleukins - between leukocytes Chemokines - chemotaxis Growth factors - proliferation and differentiation of cells Cytotoxic - eg. tumour necrosis factor
Give 3 ways in which a cytokine can act?
Autocrine - same cell receptors
Paracrine - nearby cell receptors
Endocrine - distant cells via blood circulation
Give 4 important cytokines secreted by activated macrophages?
IL1 alarm/fever
TNF alpha - alarm
IL 6 endocrine produced in production of acute phase proteins (liver)
CXCL8/IL-8 - chemokine, attracts neutrophils
